The present invention relates to a means and method of forming a needle portion of a plastice syringe, which is used, for example, for dental surgery.
Among syringes used for dental surgery, there is a type that the edge portion thereof is bent at a certain angle. This type of syringe comprises a glass made syringe tube and a steel made needle secured to the edge of the tube. This type of syringe is repeatedly used after washing, which is undesirable when a sanitary condition is concerned. Therefore, inexpensive and disposable plasitic syringes have been used recently.
Such a plastic syringe is shown, for example, in Japanese patent publication 53-21234. This syringe comprises a plastic syringe tube and a plastic thin tube which is formed separately from the syringe tube and is secured to the edge of the syringe tube, then the thin tube is heated and sharpened like a needle.
The problem with this prior art is that since the syringe tube and the thin tube are formed separately and are combined together thereafter, a lot of time is required for completing a syringe, so that productivity thereof is not satisfactory. Further, when the thin tube is heated and sharpened, some handwork has to be applied, so that a lot of experience and time are required, which detracts from productivity. Since the handwork is required, the shape of the syringe is not always accurate.
This type of syringe is supposed to be disposable, so that it should be produced by mass production and the price thereof should be kept low. However, the prior art syringe explained above is expensive, since its productivity is poor.